... "CONVERT UNITS" deselected and the dimensions are correct in TC. Saved it as a STL and loaded it into Slic3r. It complained that there are 1532 errors. I then loaded the STL into Repetier Host. That's the program that drives my 3D printer. This is how it looks in Repetier Host. 2983_051500_090000000.gif On the right it is complaining that the object is not manifold- in other words, if it was filled with water it would leak, but it gives an option to repair it, which I did. 2983_051500_090000001.gif Then I ran it through the slicer (it's Slic3r running as an extension of Repetier Host). It slices without problems. This is what the printed model would look like on my printer with its current settings. 2983_051500_090000002.gif Sometimes when I create STL files in TC they are not manifold but if it's a small number of "holes" I tend not to worry about it and just let the printer software do the repair. Shapeways doesn't seem to mind either. Meshlab should let you see where the problems are if you ...